Fundamental Limits of Non-Hermitian Sensing from Quantum Fisher Information

• URL: http://arxiv.org/abs/2603.10614v1
• Date: Wed, 11 Mar 2026 10:21:40 GMT
• Title: Fundamental Limits of Non-Hermitian Sensing from Quantum Fisher Information
• Abstract summary: We show that exceptional points (EPs) can enhance perturbation the quantum Fisher information (QFI) compared to isolated modes or diabolic points with identical decay rates.<n>This provides a unified and experimentally relevant perspective on the design of quantum-limited non-Hermitian sensors.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Exceptional points (EPs) exhibit strongly enhanced spectral responses and are therefore promising candidates for sensing applications. Whether these non-Hermitian degeneracies provide a genuine advantage in the quantum regime has been the subject of ongoing debate. Here, we address this issue within a scattering-matrix formalism for sensing with coherent light, which allows the quantum Fisher information (QFI) to be evaluated directly from experimentally accessible scattering data without introducing additional noise channels beyond those inherent to the scattering process. We analyze both nondegenerate and degenerate scattering-matrix poles, including EPs of arbitrary order, and show that the QFI per incoming photon flux is governed by three key factors: the decay rate of the resonant mode, the strength of the spectral response associated with non-normality, and the adjustment between the scattering states and the information source. For spatially localized perturbations, this implies that the Fisher information is fully determined by the local density of states at the perturbation site. Within this framework, we demonstrate that EPs can enhance the QFI compared to isolated modes or diabolic points with identical decay rates, and that the QFI can be further increased by moving away from the EP toward parameter regimes where non- Hermitian linewidth splitting reduces the decay rate of one mode. We further show that sufficiently small additional internal losses do not alter this overall picture, thereby providing a unified and experimentally relevant perspective on the design of quantum-limited non-Hermitian sensors.

Related papers

• Tunable Exceptional Points for Quantum Sensing in a Spin--Orbit-Angular-Momentum Coupled BEC [31.056304866140625]
  We investigate a tunable EP sensing platform based on the intrinsic non-Hermitian Bogoliubov dynamics of a Bose-Einstein condensate.<n>We identify multiple EPs and map their trajectories, revealing strong quantum Fisher information enhancement when the EPs are approached from the PT-symmetric stable regime.<n>We show that a spin-density measurement can approach the quantum Fisher information limit, providing an experimentally accessible route to tunable EP-enhanced quantum sensing in Bose-Einstein condensates.
  arXiv  Detail & Related papers  (2026-08-31T17:03:30Z)
• Quantum Sensing Beyond Exceptional Points via Hidden symmetry-protected vacuum-noise fixed point [7.415431423602942]
  We develop a quantum continuous-variable model that unifies parity-time (PT) and anti-paritytime(APT) symmetries within a single framework.<n>We find a hidden symmetryprotected phase transition embedded in the Hamiltonian spectrum, where collective three-mode quadratures exhibit quantum fluctuations.<n>As a consequence, quantum sensing is enhanced through the suppression of excess quantum noise while maintaining a finite response sensitivity.
  arXiv  Detail & Related papers  (2026-07-21T07:25:37Z)
• From the Hong-Ou-Mandel Effect to Quantum Sensing: Interference of Nonclassical Light with Partial Distinguishability and Noise [0.0]
  This thesis explores the interference of nonclassical states of light, particularly Fock and Gaussian states, in noisy linear interferometers.<n> analytical tools are developed to describe quantum optical interference in a unified way.
  arXiv  Detail & Related papers  (2026-07-03T23:21:47Z)
• Single-photon scattering in a dissipative superconducting-qubit--SSH lattice hybrid [14.167952153585453]
  We study single-photon scattering in a Su--Schrieffer--Heeger (SSH) photonic lattice locally coupled to a superconducting qubit with tunable loss or gain.<n>We show that the SSH dimerization, the qubit-induced non-Hermitian self-energy, and the synthetic gauge phase cooperate to reshape the reflection and transmission spectra.
  arXiv  Detail & Related papers  (2026-06-09T07:37:35Z)
• Random entanglement percolation on realistic quantum networks [51.56484100374058]
  We study random entanglement percolation in heterogeneous quantum networks.<n>We focus on polarization-dependent loss (PDL) as a physical source of random edge entanglement in photonic networks.
  arXiv  Detail & Related papers  (2026-04-23T18:00:00Z)
• Lévy-index control of spectral singularities and coherent perfect absorption in non-Hermitian space-fractional quantum mechanics [0.0]
  We analytically derive locus equations for spectral singularities (SSs) and their time-reversed counterparts, coherent perfect absorption (CPA)<n>We show that reducing the Lévy index $$, which enhances nonlocal transport associated with Lévy-flight dynamics, systematically lowers the gain-loss strength required for the emergence of SSs and CPAs.<n>This study may find applications in fractional waveguides and metamaterials governed by fractional wave equations.
  arXiv  Detail & Related papers  (2026-02-27T19:09:46Z)
• Plug-and-Play Diffusion Meets ADMM: Dual-Variable Coupling for Robust Medical Image Reconstruction [45.25461515976432]
  Plug-and-Play diffusion prior (DP) frameworks have emerged as a powerful paradigm for imaging reconstruction.<n>We present a novel approach to resolving bias-hallucination trade-off, achieving state-of-the-art gradients with significantly accelerated convergence.
  arXiv  Detail & Related papers  (2026-02-26T16:58:43Z)
• Non-Exponential Decay in Finite Photonic Waveguide Arrays [31.533307102463027]
  We study a lattice with a boundary defect that transitions between regimes controlled by a single parameter.<n>We establish a unified theory confirmed by experiments in integrated waveguide arrays.<n>This provides a benchmark for emulating infinite systems and studying open systems in photonic lattices.
  arXiv  Detail & Related papers  (2025-09-08T08:43:22Z)
• Higher-order exceptional points in a non-reciprocal waveguide beam splitter [1.5845117761091052]
  We analytically derive eigenvalues and numerically demonstrate the formation of exceptional points (EPs) in non-Hermitian systems.<n>Our results open new pathways for realizing higher-order EPs in non-reciprocal open quantum systems.
  arXiv  Detail & Related papers  (2025-03-27T12:38:58Z)
• Waveguide QED with dissipative light-matter couplings [0.9428222284377784]
  Dissipative light-matter coupling plays a vital role in non-Hermitian physics, but it remains largely unexplored in waveguide QED systems.<n>We show that by employing pseudo-Hermitian symmetry rather than anti-PT symmetry, the concept of dissipative coupling could be generalized and applied to the field of waveguide QED.<n>Thanks to the tunability of photonic bands in crystal waveguides, we also demonstrate that dissipative light-matter coupling leads to the emergence of nonstandard third-order exceptional points.
  arXiv  Detail & Related papers  (2025-03-19T04:04:28Z)
• Spectral truncation of out-of-time-ordered correlators in dissipative system [44.99833362998488]
  Out-of-time-ordered correlators (OTOCs) have emerged as powerful tools for diagnosing quantum chaos and information scrambling.<n>We investigate the spectral decomposition of OTOCs in open quantum systems using the dissipative modified kicked rotator (DMKR) as a paradigmatic model.<n>Our results provide a quantitative framework for understanding OTOCs in dissipative quantum systems and suggest new avenues for experimental exploration in open quantum platforms.
  arXiv  Detail & Related papers  (2025-03-05T17:22:25Z)
• Crossing exceptional points in non-Hermitian quantum systems [41.94295877935867]
  We reveal the behavior of two-photon quantum states in non-Hermitian systems across the exceptional point. We demonstrate a switching in the quantum interference of photons directly at the exceptional point.
  arXiv  Detail & Related papers  (2024-07-17T14:04:00Z)
• Improving On-Demand Single Photon Source Coherence and Indistinguishability Through a Time-Delayed Coherent Feedback [0.5852077003870417]
  Single photon sources (SPSs) are an essential resource for many quantum information technologies. We demonstrate how the inclusion of time-delayed coherent feedback in a scalable waveguide system, can significantly improve the two key SPS figures of merit.
  arXiv  Detail & Related papers  (2023-02-16T05:10:31Z)
• Macroscopic noise amplification by asymmetric dyads in non-Hermitian optical systems for generative diffusion models [55.2480439325792]
  asymmetric non-Hermitian dyads are promising candidates for efficient sensors and ultra-fast random number generators. integrated light emission from such asymmetric dyads can be efficiently used for all-optical degenerative diffusion models of machine learning.
  arXiv  Detail & Related papers  (2022-06-24T10:19:36Z)
• Quantum Optics of Non-Hermitian Optical Systems: Propagation of Squeezed State of Light through Dispersive non-Hermitian Optical Bilayers [0.0]
  We present a rigorous and quantum-consistent description of dispersive non-Hermitian optical bilayers. We investigate the propagation of a normally incident squeezed coherent state of light through such media.
  arXiv  Detail & Related papers  (2021-09-22T10:07:47Z)
• Observation-dependent suppression and enhancement of two-photon coincidences by tailored losses [68.8204255655161]
  Hong-Ou-Mandel (HOM) effect can lead to a perfect suppression of two-particle coincidences between the output ports of a balanced beam splitter. In this work, we demonstrate experimentally that the two-particle coincidence statistics of two bosons can instead be seamlessly tuned to substantial enhancement. Our findings reveal a new approach to harnessing non-Hermitian settings for the manipulation of multi-particle quantum states.
  arXiv  Detail & Related papers  (2021-05-12T06:47:35Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.